Part 5: Lymphoid Organs

Bone marrow

Largest tissue in the body; center of antigen-independent lymphopoiesis

Secondary/ Peripheral Lymphoid organs

Trapping site of pathogen and waiting areas of lymphocytes

Spleen

Largest secondary lymphoid organ

PALS (Periarteriolar Lymphoid Sheath)

In the spleen, the T cells can be found specifically on the _____

1/3

Fraction of platelet found in spleen

T cell

Most circulating lymphocytes

CD

Reference in standardizing names of membrane proteins found on all human white blood cells

CD2

CD marker for T cell and NK

CD3

CD marker for Mature T cell

CD4

CD marker for T helper cell

CD8

CD marker for T cytotoxic cell and macrophages

CD25

CD marker for Activated T lymphocytes, B cells, monoytes;

CD marker for IL-2

CD34

CD marker for Progenitors (HSC)

CD45

Pan-leukocyte marker ( All WBCs)

CD21

Receptor for EBV

CD

SheepRBC receptor, the classical T cell surface marker

CD2

Appears during first stage of T-cell development and remains present as identifying marker for T cell

(+) Rosette formation

CD2 binds to sheep RBC and forms ______

Eosinophils

Involved in the deletion of double-positive thymocytes

CD4

Center of Adaptive Immunity

Th1

Involved in autoimmunity

Th2

Involved in asthma and allergic reaction

CD8

Major effector in allograft rejection

Perforins and granzymes

Marker for CD8

CD3, 24, 25

CD makers for Treg

DeGerorge Syndrome (thymic hypoplasia)

Thymus gland develop abnormally.

Decreased number but normal functioning T cell

Zinc

DiGerorge Syndrome is associated with _____ deficiency of electrolyte

Nezelof syndrome

Patients are athymic

ALPS (Autoimmune Lymphoproliferative Syndrome)

TNF receptor mutation; Increase in number of lymphocytes but easily breaks down

Immature B cells (Hematogenes)

Extremely scanty cytoplasm, appearance of IgM

CD21

Receptor for a breakdown product of the complete component of C3 (C3d)

IgD

May prolong the life span of mature B cells

B Cell Immunodeficiencies

Account for more than half of immunodeficiencies

Bruton aggamaglobulinemia

Sex-linked disorder primarily affects men.

Ab fails to develop

Humoral immunity

The production of Ab by plasma cells is called ______immunity

Selective IgA Deficiency

Most common congenital immunodeficiency

X-linked Lymphoproliferative Disease (Duncan’s Disease)

Inadequate immune reaction to infection with EBV

SCID (Severe Combined Immunodeficiency)

Most severe congenital deficiency with X-liked as the most common form

SCID

T negative

B negative

Nk negative

WAS

Defined by the triad of Thrombocytopenia, Immunodeficiency, Eczema and characterized by small platelets

Ataxia Telangiectasia

T cell receptor rearrangement does not occur (problem in double negative)

1:2

CD4:CD8 ratio of AIDS

Leukemia

Malignant cells are primarily resent in the BM and peripheral blood

Lymphoma

Malignant cells arise in lymphoid tissues, such as the lymph nodes, tonsils, or spleen

MGUS (Monoclonal Gammopathy of Undetermined Significance)

Is a premalignant condition that can develop into multiple myeloma, WAS or other lymphoproliferative disorders

Acute

Rapidly progressive but have a higher response rate to therapy

Chronic

Slowly progressive but not curable

Hairy Cell Leukemia

TRAP (+)

CD103

Is highly specific and sensitive for Hairy Cell Leukemia

Hodgkin’s Lymphoma

(+) Reed-Sternberg cells

Ab to EBV

Unique to Classical Hodgkin’s Lymphoma

Nodular sclerosis Hodgkin’s Lymphoma

Most common type of HL and has the best prognosis.

Increased WBC, decreased RS cells

Mixed cellularity Hodgkin’s Lymphoma

Increased WBC, Increased RS cells

LDHL (Lymphocyte depleted Hodgkin’s Lymphoma)

Has the greatest numbers of RS cells and worst prognosis

Non-Hodgkin’s Lymphoma

Lymphoma associated with AIDS

MGUS

Increased Ab but no organ damage

Multiple Myeloma

The most serious and common of the plasma cell dyscrasias

IgG>IgA>Light chains

The most common Ab produced in Multiple myeloma

Waldenstrom’s Macroglobulinemia

Malignant proliferation of IgM producing lymphocytes which is also known as lymphoplasmacytic lymphoma

Waldenstrom’s Macroglobulinemia

(+) Hyperviscosity syndrome

(+) Cold agglutinins

(+) Frost bite

Bone marrow and biopsy

Confirmatory test for Immunoproliferative Disease

Monoclonal gammopathy

Single Ig is high with dense narrow staining in gamma region

Ficoll-Hypaque

Most commonly used method for the separation of Mononuclear cells from WB and detection of surface markers